Author Topic: CB750 rotors(charging)  (Read 3342 times)

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Offline Bill/BentON Racing

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CB750 rotors(charging)
« on: December 29, 2012, 04:11:28 PM »
Some rotor pics and weights. ;) ;D bill

in order

less weight

another

weights posted in order!
Weights
3.346 lbs no starter clutch
4.914 starter clutch missing 2 rollers,one spring and cap
5.792
6.004
5.834
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
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Offline Greggo

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Re: CB750 rotors(charging)
« Reply #1 on: December 29, 2012, 04:14:52 PM »
8) 8) 8) 8)

Offline MRieck

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Re: CB750 rotors(charging)
« Reply #2 on: December 29, 2012, 04:49:56 PM »
The first one doesn't charge....the others do in poor order./ ;)
Owner of the "Million Dollar CB"

Offline Big Jay

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Re: CB750 rotors(charging)
« Reply #3 on: December 29, 2012, 04:54:20 PM »
We used to cut those down. Especially the older ones with the big flange. Once we got them about as light as we could, they couldn't keep the battery charged. When they came out with the always on headlight deal, we quit doing it altohether.

Offline bwaller

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Re: CB750 rotors(charging)
« Reply #4 on: December 29, 2012, 05:24:09 PM »
What is attached to that dog leg Bill? Man the poor cave is thinning down, you know you'll only have to clean up as space becomes available. Please don't sell the roadracer, slowly but surely TimV & I are racing our way towards you. You'll see the light again, promise!  ;)

Offline scottly

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Re: CB750 rotors(charging)
« Reply #5 on: December 29, 2012, 05:36:29 PM »
The rotor on the left of the attached pic is a stock K7 rotor. 2079 grams = 4.57 lbs. The one on the right is a cut down K1 rotor; that's as far as I could pare it down without affecting the charging.
Don't fix it if it ain't broke!
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Offline cbr954

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Re: CB750 rotors(charging)
« Reply #6 on: December 29, 2012, 05:37:24 PM »
I have a lightened rotor from Cycle X, still seems to keep the battery charged.  I really like how it helped make the motor quicker revving.  It weighs about 4.75 lbs.
03 CBR954RR, 72 750 chopper(970cc
F2 head), 2017 CRF450R, 2001 CR250R, 72 CB500, 79 XR250, 04 CRF50,70's soon to be rebuilt cb750 drag bike.

Offline 754

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Re: CB750 rotors(charging)
« Reply #7 on: December 30, 2012, 09:24:08 AM »
 Mine is like the lightest one, kept battery charged fine with a small battery, i run 72 and earlier headlight switch, you can turn light off, while starting warmup, etc.
 Scottly you can take more out that one. Drill the starter clutch holes to 5/8 or so, then 3 more in between..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Bill/BentON Racing

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Re: CB750 rotors(charging)
« Reply #8 on: December 30, 2012, 10:29:59 AM »
What is attached to that dog leg Bill? Man the poor cave is thinning down, you know you'll only have to clean up as space becomes available. Please don't sell the roadracer, slowly but surely TimV & I are racing our way towards you. You'll see the light again, promise!  ;)
Roadracer going nowhere til I build it again......one day......tho I keep selling Greggo all my good 550 stuff!Bill
BentON Racing Website
OEM Parts | Service | Custom Builds
BentON Racing Facebook
Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
______________________________________
See our latest build 'Captain Marvel' CLICK HERE

Offline Greggo

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Re: CB750 rotors(charging)
« Reply #9 on: December 30, 2012, 03:20:31 PM »
Roadracer going nowhere til I build it again......one day......tho I keep selling Greggo all my good 550 stuff!Bill

Bill, you just need to buy one of my turbos ;) 8)

Offline Stev-o

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Re: CB750 rotors(charging)
« Reply #10 on: December 30, 2012, 07:12:41 PM »
Roadracer going nowhere til I build it again......one day......tho I keep selling Greggo all my good 550 stuff!Bill


Ahhh.... now I know where Greggo's been getting all the cool hi po parts....
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline scottly

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Re: CB750 rotors(charging)
« Reply #11 on: January 01, 2013, 05:50:58 PM »

 Scottly you can take more out that one. Drill the starter clutch holes to 5/8 or so, then 3 more in between..
Those holes might remove 70-80 grams, but would reduce the charging, due to the loss of the area exposed to magnetic flux from the end of the field coil. I didn't remove any material on the ID at the open end of the rotor for the same reason.
The starter clutch, including the 3 mounting screws, weighs 1.23 lbs.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline MRieck

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Re: CB750 rotors(charging)
« Reply #12 on: January 01, 2013, 07:00:44 PM »
I'm just waiting for a modern, 600cc unit with a permanent magnet to show up. Maybe 400 Watts all day....and half the weight. Who knows....it might happen. ;) ;) ;D
Owner of the "Million Dollar CB"

Offline scottly

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Re: CB750 rotors(charging)
« Reply #13 on: January 01, 2013, 07:19:01 PM »
CB 750 stator= 2.438 lbs
CB750 field= 2.706 lbs.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline scottly

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Re: CB750 rotors(charging)
« Reply #14 on: January 01, 2013, 07:39:51 PM »
I'm just waiting for a modern, 600cc unit with a permanent magnet to show up. Maybe 400 Watts all day....and half the weight. Who knows....it might happen. ;) ;) ;D
I would be happy with a unit that produces stock power, with half the weight. ;)
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline Retro Rocket

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Re: CB750 rotors(charging)
« Reply #15 on: January 01, 2013, 08:06:08 PM »
I'm just waiting for a modern, 600cc unit with a permanent magnet to show up. Maybe 400 Watts all day....and half the weight. Who knows....it might happen. ;) ;) ;D

VFR800..... ;)
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline 754

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Re: CB750 rotors(charging)
« Reply #16 on: January 01, 2013, 09:01:36 PM »
I got a 750 nighthawk unit rotor is under 3 lbs..iirc
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way